This Application claims the benefit of the Application Number 0003485 filed Mar. 17, 2000 in France, which is incorporated herein by reference.
This invention relates to a draw-out unit for electrical switchgear cabinets. More specifically, this invention relates to a draw-out unit for mounting a molded case circuit breaker in a switchgear cabinet.
The use of switchgears in electrical distribution systems is well known. The switchgear houses a plurality of draw-out units, with each draw-out unit housing one or more switching devices, such as motor controllers and circuit breakers, releasably interconnected to one or more busbars. Periodically, the draw-out units are removed from the switchgear to allow for maintenance of equipment. The switching devices within the draw-out units make electrical contact with the busbars through a plurality of clip connectors, which extend from the draw-out unit. Each clip connector is electrically connected to an electrical conductor for connection to the switching devices of the switchgear. As the draw-out unit is inserted into the switchgear, the busbar slides between the two contact arms, and the contact arms frictionally engage the busbar.
Draw-out mechanisms are known in the art for use with molded case circuit breakers. One such mechanism is described in U.S. Pat. No. 4,743,715 issued May 10, 1988. These mechanisms have discrete positions for testing, installing and removing the circuit breaker. The positions are CONNECT, DISCONNECT and TEST. In the CONNECT position the circuit breaker can be closed, opened or tripped. In the DISCONNECT position the circuit breaker is in the trip position and the draw-out mechanism can be locked to prevent access to the circuit breaker. The third position is TEST, wherein the circuit breaker is disconnected from the main circuit. In the TEST position the circuit breaker can be closed, opened or tripped in order to check internal and external accessories such as auxiliary switches, shunt trip and under voltage and secondary circuits. However, draw-out mechanisms with a xe2x80x9ctestxe2x80x9d position relate to air circuit breakers (ACB""s), which are large in size. Because these draw-out mechanisms are larger in size, they also tend to be costly to produce.
A draw-out mechanism for mounting a circuit breaker within a switchgear cabinet includes a fixed side plate arranged for mounting within the switchgear cabinet. The draw-out mechanism also includes a mobile side plate having a first pin extending therefrom. The circuit breaker is arranged to move in cooperation with the mobile side plate. A cam is pivotally disposed on the fixed side plate. The cam includes a slot disposed therein for accepting the pin extending from the mobile side plate. The pin slides within the slot as the cam pivots, thus moving said mobile side plate relative to said fixed side plate.